Electric washing machine

ABSTRACT

An electric washing machine according to the present invention performs a washing process for washing laundry without the use of a detergent by generating water streams in an outer tub ( 2 ) containing an electrolyzed liquid produced through electrolysis by an electrolyzing device ( 31 ) when a zero detergent course is selected by a user. The electrolyzing device ( 31 ) is provided as a water treatment unit ( 60 ) attached to a lower portion of an outer side surface ( 66 ) of the outer tub ( 2 ), and includes a thin-box-shaped electrolyzing chamber ( 32 ), a pair of electrodes ( 33 ) supported at opposite edges thereof, and a pair of water communication paths ( 34, 35 ). The pair of water communication paths ( 34, 35 ) are disposed in a vertically juxtaposed relation to connect the outer tub ( 2 ) to the electrolyzing chamber ( 32 ) with the intervention of packings ( 81 ). Thus, an assembling operation and the like can conveniently be performed, and water can efficiently be electrolyzed for use in the washing process.

TECHNICAL FIELD

[0001] The present invention relates to an electric washing machine.

PRIOR ART

[0002] Electric washing machines usually perform a washing process withthe use of a detergent.

SUMMARY OF THE INVENTION

[0003] It is a main object of the present invention to provide anelectric washing machine which is capable of washing laundry without theuse of a detergent.

[0004] In accordance with a first aspect of the present invention, thereis provided an electric washing machine comprising: a washing tub forcontaining laundry; water stream generating means for generating waterstreams in the washing tub; water treatment means for performing aspecific treatment on tap water to be supplied into the washing tub ortap water supplied into the washing tub to impart the water with acleaning capability without addition of a detergent; storage means whichstores therein a sequence for a first washing course in which thelaundry is washed by generating water streams in the washing tub whichcontains a detergent solution prepared by adding the detergent into thetap water, and a sequence for a second washing course in which thelaundry is washed without the use of the detergent by generating waterstreams in the washing tub which contains a cleaning liquid impartedwith the cleaning capability by treating the tap water by the watertreatment means; selecting means for allowing a user to select the firstwashing course or the second washing course; and control means forcontrolling operations of the water stream generating means and thewater treatment means on the basis of the sequence for the washingcourse selected by the selecting means to perform a washing process inthe selected washing course.

[0005] More specifically, the water treatment means includes a pair ofelectrodes for electrolysis of the tap water, and is adapted to producethe cleaning liquid by electrolyzing the tap water through energizationof the pair of electrodes.

[0006] In the aforesaid arrangement, the machine preferably furthercomprises load detecting means for detecting a load of the laundry andinformation means for notifying a detergent amount according to the loaddetected by the load detecting means, wherein the control means actuatesthe load detecting means for the detection of the load and causes theinformation means to notify the detergent amount according to thedetected load in the washing process of the first washing course, andprohibits the information means from notifying the detergent amount inthe washing process of the second washing course.

[0007] The machine preferably further comprises second information meansfor notifying that no detergent is added, wherein the control meansactuates the second information means in the washing process of thesecond washing course.

[0008] Alternatively, the machine preferably further comprises loaddetecting means for detecting a load of the laundry, and adding meansfor adding the detergent in an amount according to the load detected bythe load detecting means, wherein the control means actuates the loaddetecting means for the detection of the load and causes the addingmeans to add the detergent in the amount according to the detected loadin the washing process of the first washing course, and prohibits theadding means from adding the detergent in the washing process of thesecond washing course.

[0009] In the aforesaid arrangements, where the first washing course isselected by the user, the water streams are generated in the washing tubcontaining the detergent solution (prepared by adding the detergent intothe tap water) for washing the laundry in the washing process. Morespecifically, the load of the laundry contained in the washing tub isdetected. Then, the detergent amount according to the detected load isnotified (by display or voice), and the user adds a proper amount of thedetergent on the basis of the notification. Alternatively, the detergentis automatically added according to the detected load.

[0010] A place where the detergent is added is, for example, the washingtub or a detergent box. That is, the place may be where the detergent ismixed with the water contained in the washing tub.

[0011] When the water containing the detergent (detergent solution) iscontained in the washing tub, the water streams are generated forwashing the laundry. Dirt adhering to the laundry is removed by theeffect of the detergent and the effect of the water streams.

[0012] Where the second washing course is selected by the user, thewater streams are generated in the washing tub containing the cleaningliquid (e.g., electrolyzed liquid) produced through the treatment by thewater treatment means for washing the laundry without the use of thedetergent in the washing process.

[0013] More specifically, the pair of electrodes are disposed in a spacewhere the tap water in the washing tub can be electrolyzed, for example,in the washing tub or a chamber communicating with the washing tub.First, the water is retained in the washing tub. Then, the water in thewashing tub is electrolyzed through energization of the pair ofelectrodes for production of the electrolyzed water as the cleaningliquid. In the electrolyzed water contained in the washing tub, thewater streams are generated for washing the laundry. In this washingprocess, the information on the detergent amount according to the loadis not given, but addition of no detergent is notified. Alternatively,the automatic addition of the detergent is not effected.

[0014] The tap water contains very small amounts of impurities such asiron, calcium, magnesium and chlorine, and the electrolysis thereofprovides the following effects. That is, the electrolyzed water isneutral to alkaline. In addition, active oxygen is generated. Further,hypochlorous acid and hypochlorous ions are generated. Dirt adhering tothe laundry is removed by the effect of the alkaline water, the effectof the active oxygen and the effect of the water streams. In addition,the laundry is sterilized by the effect of hypochlorous acid andhypochlorous ions.

[0015] The washing operation by the water streams may be performedduring the water treatment (electrolysis), or after the water treatment.Rather than the treatment (electrolysis) of the tap water contained inthe washing tub, the water treatment means (the pair of electrodes) maybe provided upstream of the washing tub, so that the tap water istreated for the production of the cleaning liquid which is in turnsupplied into the washing tub.

[0016] With the aforesaid arrangements, the washing course for washingthe laundry without the use of the detergent can be realized, so thatthe amount of the detergent to be used can drastically be reduced.

[0017] Further, the information on the detergent amount according to theload is provided in the first washing course employing the detergent,and is not provided in the second washing course employing no detergent.Therefore, the proper amount of the detergent can be added without anyexcess or shortage in the first washing course, and the use of nodetergent can expressly be notified to prevent the user from mistakenlyadding the detergent in the second washing course employing nodetergent.

[0018] In the second washing course, the use of no detergent isnotified, thereby assuredly preventing the user from adding thedetergent.

[0019] The detergent is automatically added in an amount according tothe load in the first washing course employing the detergent, and theautomatic addition of the detergent is not effected in the secondwashing course employing no detergent. Therefore, the proper amount ofthe detergent can be added without any excess or shortage in the firstwashing course, and wasteful use of the detergent can be prevented inthe second washing course employing no detergent.

[0020] In accordance with another aspect of the present invention, thereis provided an electric washing machine which is adapted to selectivelyeffect a first washing course in which laundry is washed with the use ofa detergent and a second washing course in which the laundry is washedin a manner different from the first washing course without the use ofthe detergent.

[0021] With the aforesaid arrangement, the washing course for washingthe laundry without the use of the detergent is realized, so that theamount of the detergent to be used can drastically be reduced.

[0022] In accordance with further another aspect of the presentinvention, there is provided an electric washing machine comprising awater treatment unit for electrolyzing water in use for a washingprocess to impart the water with a cleaning capability without additionof a detergent, the water treatment unit being attached to the outsideof a washing tub.

[0023] Thus, the amount of the detergent to be used can be reduced, andthe water treatment unit can easily be handled from the outside of thewashing tub. Therefore, a mounting operation for mounting the watertreatment unit on the washing tub, a maintenance operation for the watertreatment unit and a disassembling operation for recycling, for example,can be facilitated.

[0024] In the aforesaid arrangement, the water treatment unit preferablyincludes an electrolyzing chamber, at least one pair of electrodesdisposed in the electrolyzing chamber, and a pair of water communicationpaths extending from the electrolyzing chamber, the pair of watercommunication paths being connected to the washing tub, wherein thewater flows into the electrolyzing chamber from the washing tub throughone of the water communication paths, and the water treated in theelectrolyzing chamber flows out into the washing tub through the otherwater communication path.

[0025] Thus, the water treatment unit can unitarily be handled in theassembling and maintenance operations, so that these operations arefurther facilitated.

[0026] Since the pair of water communication paths ensure efficientwater communication between the electrolyzing chamber and the washingtub, the treated water can be supplied into the washing tub forefficient use in the washing process without waste, and the water fromthe washing tub is caused to flow within the electrolyzing chamber forefficient electrolysis.

[0027] In the aforesaid arrangement, the electrolyzing chamberpreferably has a thin box shape having a smaller depth with respect toan outer surface of the washing tub, and the electrodes preferably eachhave a plate shape corresponding to the thin box shape of theelectrolyzing chamber. The plate-shaped electrodes are preferablydisposed at a predetermined inter-electrode pitch with opposite edgesthereof being supported.

[0028] Thus, the projection of the water treatment unit from the outersurface of the washing tub can be reduced for space saving.

[0029] Since the electrodes are held at the opposite edges thereof inthe box-shaped electrolyzing chamber, the water treatment unit can behandled without careful attention. Therefore, the assembling,maintenance and disassembling operations can be facilitated.

[0030] In the aforesaid arrangement, the electrolyzing chamber ispreferably mounted on an outer side surface of the washing tub. The onewater communication path (inlet path) preferably extends from a lowerportion of the electrolyzing chamber, and the other water communicationpath (outlet path) preferably extends from an upper portion of theelectrolyzing chamber. The water communication paths are preferablyconnected to the washing tub with the intervention of packings.

[0031] With the use of the packings, dimensional errors can beaccommodated when the water treatment unit is mounted on the washingtub, so that the mounting can easily be achieved. In addition, sealingof gaps between the water communication paths and the washing tub can beachieved.

[0032] Since the pair of water communication paths are provided atdifferent vertical positions of the thin-box-shaped electrolyzingchamber attached to the outer side surface of the washing tub, verticalwater flow is facilitated for efficient electrolysis.

[0033] In the aforesaid arrangement, the upper portion of theelectrolyzing chamber is preferably inclined with one side thereoflocated at a higher position, and the outlet path preferably extendsfrom the higher position. The inlet path preferably extends from a lowerend of the electrolyzing chamber. Thus, the water flow in theelectrolyzing chamber can be facilitated.

[0034] In the aforesaid arrangement, an air supply port for supplyingair is preferably provided at a lower portion of the electrolyzingchamber, whereby the air supplied into the electrolyzing chamber fromthe air supply port flows into the washing tub through the upper watercommunication path, and the water contained in the electrolyzing chamberis caused to flow by the air flow. Thus, the water flow in theelectrolyzing chamber can be facilitated for efficient electrolysis. Inaddition, the air is introduced into the washing tub, therebycontributing to improvement of the cleaning capability.

[0035] In the aforesaid arrangement, the air is preferably suppliedwithout contact with the electrodes. Thus, reduction in electrolysisefficiency due to the air can be suppressed.

[0036] In the aforesaid arrangement, the electrodes preferably each havea round corner, and a spacing between the electrodes and a spacingbetween each of the electrodes and the electrolyzing chamber arepreferably such that lint is prevented from being caught therebetween.Thus, the lint is less liable to adhere onto the electrodes, so thatreduction in electrolysis efficiency due to the lint can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037]FIG. 1 is a side sectional view of a fully automatic washingmachine according to one embodiment of the present invention;

[0038]FIG. 2 is a partly sectional front view of the fully automaticwashing machine shown in FIG. 1;

[0039]FIG. 3 is a partly sectional side view of a water treatment unit;

[0040]FIG. 4 is a schematic diagram schematically illustrating theconstruction of the water treatment unit as viewed from the front sidethereof;

[0041]FIG. 5 is a plan view of an operation panel for illustrating theconstructions of an operation section and a display section;

[0042]FIG. 6 is a diagram illustrating the electrical construction ofthe fully automatic washing machine according to the embodiment;

[0043]FIG. 7 is a flow chart for explaining a washing process in astandard course to be performed by the fully automatic washing machineaccording to the embodiment; and

[0044]FIG. 8 is a flow chart for explaining a washing process in a zerodetergent course to be performed by the fully automatic washing machineaccording to the embodiment.

EMBODIMENTS OF THE INVENTION

[0045] A fully automatic washing machine according to one embodiment ofthe present invention will hereinafter be described with reference tothe attached drawings.

[0046]FIG. 1 is a side sectional view illustrating the construction ofthe fully automatic washing machine according to this embodiment. Abottomed cylindrical outer tub 2 is suspended in a forwardly inclinedmanner within a housing 1 of the washing machine by front suspensionrods 3 and rear suspension rods 4 (though one front suspension rod andone rear suspension rod are shown in the figure, there are two frontsuspension rods and two rear suspension rods). A front upper portion ofthe housing 1 projects forward correspondingly to the forward projectionof an upper portion of the inclined outer tub 2. The housing 1 has awidely open front portion 16, which is covered with a detachable frontpanel 17. Therefore, an upper portion of the front panel 17 projectscorrespondingly to the projection of the upper portion of the outer tub2.

[0047] A washing/dehydration tub (inner tub) 5 having a multiplicity ofdehydration perforations formed in a circumferential wall thereof issupported within the outer tub 2 rotatably about a dehydration shaft 6thereof. The outer tub 2 and the inner tub 5 constitute a washing tubaccording to the present invention. A pulsator 7 (water streamgenerating means) for generating water streams for agitation of laundryis disposed on an inner bottom portion of the inner tub 5. A drivingmechanism 10 for driving the pulsator 7 and the inner tub 5 is providedat the bottom of the outer tub 2. The driving mechanism 10 includes thedehydration shaft 6, a pulsator shaft 9 provided in the dehydrationshaft 6 for rotating the pulsator 7, a motor 8 provided coaxially withthe dehydration shaft 6 and the pulsator shaft 9, and a clutch forswitchably transmitting power of the motor 8 only to the pulsator shaft9 or to both the pulsator shaft 9 and the dehydration shaft 6. Thedriving mechanism 10 principally rotates only the pulsator 7 in onedirection or in opposite directions in a washing operation and a rinsingoperation, and unitarily rotates the inner tub 5 and the pulsator 7 inone direction (or in a normal direction) in a dehydrating operation. Theinner tub 5 is rotated once by each turn of the motor 8. On the otherhand, a reduction gear mechanism (not shown) is provided in a middleportion of the pulsator shaft 9, so that the pulsator 7 is rotatedaccording to a reduction radio of the reduction gear mechanism.

[0048] A water supply port 11 having a detergent container 11 a forsupplying a detergent contained therein is provided on an upper rearside of the outer tub 2. A water supply tube 12 having a water supplyvalve 13 provided in a middle portion thereof is connected to the watersupply port 11. When the water supply valve 13 is opened, tap water issupplied to the water supply port 11 from an external tap through thewater supply tube 12. Thus, the tap water flows downward into the outertub 2 from the water supply port 11. One end of a water drainage tube 14is connected to a front bottom portion or lowermost portion of the outertub 2. The water drainage tube 14 is opened and closed by a waterdrainage valve 15. The other end of the water drainage tube 14 isconnected to an external sewage drain through a self-standing hose notshown. The opening and closing of the water drainage valve 15 areassociated with the switching of the aforesaid clutch. When a torquemotor (not shown in FIG. 1) is not operated, the pulsator 7 is decoupledfrom the inner tub 5 so as to be solely rotated with the water drainagevalve 15 being closed. When the torque motor is operated to pull a wireto the midst, the pulsator 7 is coupled to the inner tub 5 with thewater drainage valve 15 being closed. When the wire is further pulled,the water drainage valve 15 is opened with the pulsator 7 kept coupledto the inner tub 5.

[0049] In the washing machine according to this embodiment, the outertub 2 and the inner tub 5 are inclined forward as described above, sothat open tops of the outer tub 2 and the inner tub 5 are directedforward with respect to a vertically upward direction. That is, a centerline CL of the outer tub 2 is tilted at a predetermined tilt angle αwith respect to a vertical line VL. Thus, a user standing in front ofthe washing machine can easily view the bottom of the inner tub 5 andeasily take out the laundry. A tilt angle α of about 5 degrees to about20 degrees ensures easy take-out of the laundry, and yet suppresses theforward projection of the housing 1. In this embodiment, the tilt angleα is set at about 10 degrees.

[0050] An electrolyzing device 31 as water treatment means is disposedon a lower portion of a circumferential wall of the outer tub 2. Theelectrolyzing device 31 is provided as a unit separate from the outertub 2, and fixed to the outer tub 2 by screws or the like. Theelectrolyzing device 31 is located on a front side of the outer tub 2,and appears when the front panel 17 is removed. This arrangementfacilitates the repair and replacement of the electrolyzing device 31.

[0051] The electrolyzing device 31 includes an electrolyzing chamber 32provided separately from the outer tub 2, a pair of electrodes 33disposed in the electrolyzing chamber 32, an upper water communicationpath 34 connecting an upper portion 69 of the electrolyzing chamber 32to the outer tub 2, and a lower water communication path 35 connecting alower portion of the electrolyzing chamber 32 to the outer tub 2.

[0052] The pair of electrodes 33 include a first electrode 33 a and asecond electrode 33 b. The first electrode 33 a and the second electrode33 b each have a thin square plate shape. The electrolyzing chamber 32is configured in a thin box shape having a smaller depth (indicated byD1 in FIG. 3) with respect to the circumferential wall of the outer tub2. The first electrode 33 a and the second electrode 33 b are disposedin predetermined spaced relation in the electrolyzing chamber 32 withsurfaces thereof facing toward the circumferential wall of the outertub. This arrangement suppresses the projection of the electrolyzingdevice 31 provided on the circumferential surface of the outer tub 2.Thus, the electrolyzing device 31 is prevented from bumping against thehousing 1 when the outer tub 2 vibrates during the dehydratingoperation.

[0053] It is also conceivable that the electrolyzing chamber 32 of theelectrolyzing device 31 is provided integrally with the outer tub 2 andthe electrodes 33 are provided inside the outer tub 2. In this case,however, it is difficult to mount the electrodes 33 in a narrow spaceinside the outer tub 2 and to take out the electrodes 33 for maintenanceand recycling. This is why the electrolyzing device 31 is provided as aunit, i.e., as a water treatment unit 60, which can be mounted outsidethe outer tub 2.

[0054] The water treatment unit 60 is constructed so as to be handledunitarily in the assembling. For example, the water treatment unit hasthe electrolyzing chamber 32, the pair of electrodes 33 disposed in theelectrolyzing chamber 32, and the pair of water communication paths 34,35 extending from the electrolyzing chamber 32, so as to solelyconstitute the aforesaid electrolyzing device 31. The electrolyzingchamber 32 and the pair of water communication paths 34, 35 areintegrally formed of a synthetic resin.

[0055] The water treatment unit 60 is mounted on a front lower rightportion of the outer tub 2 as seen from the front side thereof in FIG. 2in an open space defined between a corner of the housing 1 and the outertub 2. An energization circuit 30 (see FIG. 6) is electrically connectedto the water treatment unit 60. The energization circuit 30 has atransformer 61 and the like. The transformer 61 which typically has agreater weight is stably fixed to a highly strong front portion 62 of aright corner of the housing 1 as seen from the front side thereof. Thetransformer 61 may be fixed to the bottom 64 of the outer tub 2. In thiscase, the vibrations of the outer tub 2 can advantageously be suppressedby utilizing the great weight of the transformer 61.

[0056] The water treatment unit 60 and the transformer 61 are located inthe vicinity of the open portion 16 of the housing 1 and, therefore,easily accessed through the open portion 16 for an assembling operation,a maintenance operation for repair, replacement or the like, and adisassembling operation for recycling. Further, the water treatment unit60 and the transformer 61 are closely located, so that electricalconnection therebetween is easily established. Since the water treatmentunit 60 and the transformer 61 are detachably fixed by screws, theaforesaid operations can advantageously be performed.

[0057] The water treatment unit 60 and the transformer 61 are fixed at aposition remote from electrical components for controlling motorrotation such as a rotation sensor 24 (see FIG. 6) provided in the motor8 and a control circuit board 65 fixed to a front left portion 63 of thehousing 1 and including an invertor driving section 23 (see FIG. 6), andinterconnection components (not shown) connecting these components.Thus, noises caused by the transformer 61 during electrolysis can beprevented from exerting an adverse effect on the control of the rotationof the motor 8.

[0058] As shown in FIG. 3, the electrodes 33 are disposed parallel tothe largest face, e.g., a front face portion 71, of the thin-box-shapedelectrolyzing chamber 32, and each have a plate shape having a sizecorresponding to the size of the front face portion 71. Since theelectrodes 33 thus have greater areas, a requirement for the surfaceareas is satisfied by a minimum number of electrodes 33. The electrodes33 are formed of a metal, and disposed in opposed relation. Theplate-shaped electrodes 33 are supported at a predeterminedinter-electrode pitch with opposite sides of plate faces thereof oropposite edges thereof being held. Opposite polarities are respectivelyapplied to the pair of electrodes 33 for the electrolysis of the water.

[0059] The arrangement of the electrodes 33 is not limited to the pairof electrodes having the opposite polarities. For example, threeelectrodes 33 may be disposed in juxtaposition with plate surfacesthereof opposed to each other. Alternatively, five electrodes 33 maybedisposed in juxtaposition with plate surfaces thereof opposed to eachother. In these cases, the polarities of the electrodes 33 arealternated so that each adjacent pair of electrodes 33 have oppositepolarities. What is important is that at least one pair of electrodes 33are provided. Therefore, the following description is directed to a casewhere one pair of electrodes 33 are provided.

[0060] The vertically opposite edges of the electrodes 33 are held bythe electrolyzing chamber 32. Upper edges of the electrodes 33 are heldin recesses 77 formed in the electrolyzing chamber 32. These recesses 77are defined between a pair of ribs projecting inward from a top faceportion 75 of the electrolyzing chamber 32. Lower edges of theelectrodes 33 are held by a bottom face portion 76 of the electrolyzingchamber 32 via terminal covers 85. The terminal covers 85 cover thelower edges of the electrodes 33, and seal gaps between the bottom faceportion 76 of the electrolyzing chamber 32 and the lower edges of theelectrodes 33 for prevention of accumulation of lint. The electrodes 33may be supported at laterally opposite sides thereof.

[0061] The inter-electrode pitch (indicated by D2), more specifically, aspacing (indicated by D3) between the electrodes 33, is preferably notsmaller than 2 mm and not greater than 5 mm, for example. If the spacingis smaller than 2 mm, the lint is liable to come into a space betweenthe electrodes 33 and adhere on the electrodes, thereby reducing theelectrolysis efficiency and the durability. If the spacing is greaterthan 5 mm, application of a higher voltage is required for maintainingthe electrolysis efficiency at a high level, making practicalconstruction difficult. With a spacing of not smaller than 2 mm and notgreater than 5 mm, a practically high durability and a high electrolysisefficiency can be realized.

[0062] It is conceivable that the electrolyzing chamber 32 is formed ofa material different from the material for the outer tub 2 or,alternatively, of the same material as the outer tub 2. In the lattercase, the electrolyzing chamber 32 can easily be handled for recyclingthereof. For example, the electrolyzing chamber 32 is formed of anolefin resin such as polypropylene (PP). This resin is also employed asthe material for the outer tub 2 to impart the outer tub with a chemicalresistance to water containing agents such as a detergent and ableaching agent. Further, addition of a reinforcing material such asglass fibers to the material for the electrolyzing chamber 32advantageously suppresses reduction in the strength of the tub due toincrease in water temperature.

[0063] As shown in FIGS. 3 and 4, the electrolyzing chamber 32 has thebottom face portion 76, the front face portion 71, a rear face portion72, a right side face portion 73 and a left side face portion 74 whichextend upright from the periphery of the bottom face portion 76, and thetop face portion 75. The electrodes 33 are disposed in a space definedby the face portions 71 to 76, and water is retained in the space. Theelectrolyzing chamber 32 is configured so as to have a smaller dimensionas measured from the front face portion 71 to the rear face portion 72.The electrodes 33 are disposed generally parallel to the front faceportion 71. The electrolyzing chamber 32 is constituted by a pair ofvertically separable bodies 78, 79 (see FIG. 2).

[0064] An upper portion 69 of the electrolyzing chamber 32 is inclinedwith one side thereof located at a higher position. That is, the topface portion 75 of the electrolyzing chamber 32 is inclined upwardtoward the right side thereof as seen from the front side thereof. Theupper water communication path 34 extends from a part of the rear faceportion 72 at the higher position. The lower water communication path 35extends from a part of the rear face portion 72 at a lower position ofthe electrolyzing chamber 32.

[0065] The pair of water communication paths 34, 35 are arrangedgenerally parallel to each other in vertically juxtaposed relation. Thewater communication paths 34, 35 are tubes having a round section andformed integrally with the rear face portion 72 of the electrolyzingchamber 32. The shape of the pair of water communication paths 34, 35 isnot limited to the tubular shape, as long as spaces are defined thereinfor communication between the inside of the electrolyzing chamber 32 andthe inside of the outer tub 2 for water passage. It is also conceivableto provide the water communication paths separately from theelectrolyzing chamber 32 or integrally with the outer tub 2.

[0066] The water flows into the electrolyzing chamber 32 from the outertub 2 through the lower water communication path 35. Water treated inthe electrolyzing chamber 32 flows out into the outer tub 2 through theupper water communication path 34. The water is caused to flow in thismanner, for example, by the water streams generated in the outer tub 2by the rotation of the pulsator 7.

[0067] The way of the water flow in the pair of water communicationpaths 34, 35 is not particularly limited, but it is also conceivablethat the water flows in a direction opposite to that described above. Itis merely necessary that the pair of water communication paths 34, 35are provided for the water inlet and the water outlet, and it is alsoconceivable that at least one of the water communication paths includesa plurality of water communication paths, e.g., three or more watercommunication paths. It is also conceivable that the pair of watercommunication paths are provided unitarily or as a single watercommunication path. For example, the single water communication path isnot divided into two water communication paths for the water inlet andthe water outlet, but may double as a water inlet path and a wateroutlet path. The following description is directed to a case where thelower water communication path 35 and the upper water communication path34 serve as the water inlet path and the water outlet path,respectively.

[0068] As shown in FIG. 3, the pair of water communication paths 34, 35are connected to the outer tub 2 via packings 81. The packings for thewater communication paths 34, 35 have the same construction and,therefore, an explanation will be given only to the packing for thewater communication path 34.

[0069] The packing 81 is a cylindrical elastic component such ascomposed of a rubber. The packing 81 is fitted around the watercommunication path 34. The packing 81 is press-fitted in a connectionport 67 formed on an outer surface 66 (circumferential wall) of theouter tub 2 externally of the outer tub 2. The packing 81 has a longsealing distance between the tubular water communication path 34 and theconnection port 67. The packing 81 is fitted in a predetermined radiallycompressed manner to seal a gap between the inner circumference of theconnection port 67 and the outer circumference of the watercommunication path 34. The packing 81 is elastically deformable in itsradial and axial directions. Thus, the packing 81 accommodatesdimensional errors in the connection port 67 and the water communicationpath 34. Further, the packing 81 can accommodate a dimensionaldifference between a pitch of the pair of water communication paths 34,35 and a pitch of the pair of connection ports 67. The packing 81accommodates thermal deformation of the outer tub 2 occurring when hotwater is retained in the outer tub 2. Thus, breakage and water leakagecan be prevented.

[0070] Besides the cylindrical packing, an O-ring and a sheet packingmay be employed as the packing 81.

[0071] The electrolyzing chamber 32 has a plurality of fixing portions,e.g., four fixing portions 80, provided in the vicinity of the pair ofwater communication paths 34, 35 for fixing the electrolyzing chamber 32to the outer tub 2 by screws. The screws 86 extending throughthrough-holes of the fixing portions 80 are externally screwed intobosses 68 projecting from the outer surface 66 of the outer tub 2.

[0072] Terminals 84 of the electrodes 33 extend outward through thebottom face portion 76 of the electrolyzing chamber 32 as shown in FIG.4. Even if water drops adhere on the outer surface of the electrolyzingchamber 32 due to water condensation and overflow of the water from thewashing tub, a short-circuit between the terminals 84 of the pair ofelectrodes 33 is less liable to occur due to the water drops. Thus, theterminals 84 can electrically be isolated from each other. Further, aseparation plate 87 is provided for separating the terminals 84 of thepair of electrodes 33 from each other. The separation plate 87 preventsmovement of the water drops to ensure the electrical isolation. Theseparation plate 87 may double as the fixing portion 80 formedintegrally with the electrolyzing chamber 32 for reduction of the numberof the components.

[0073] The water treatment unit 60 is assembled in the following manner.With the separable bodies 78, 79 of the electrolyzing chamber 32 beingseparated from each other, the electrodes 33 are set in one 78 of theseparable bodies. Then, the pair of separable bodies 78, 79 are combinedwith each other, and seams thereof are sealed. Thus, the assembling ofthe water treatment unit 60 is completed. The water treatment unit 60having the box-shaped electrolyzing chamber 32 per se can be tested, forexample, for the sealing property and the electrolysis performancethereof, before it is mounted on the outer tub 2. Then, the pair ofwater communication paths 34, 35 are externally press-fitted in theconnection ports 67 of the outer tub 2 with the intervention of thepackings 81. The fixing portions 80 of the electrolyzing chamber 32 arerespectively fixed to the bosses 68 of the outer tub 2 by screws. Theterminals 84 of the electrodes 33 are electrically connected to theenergization circuit 30. Further, the water treatment unit 60 can beremoved from the outer tub 2 by performing the aforesaid operations in areverse order. Thus, the maintenance operation and the disassemblingoperation for the recycling can be facilitated.

[0074] Since the water treatment unit 60 is thus provided on the outsideof the outer tub 2, the mounting operation for mounting the watertreatment unit 60 on the outer tub 2, the maintenance operation for thewater treatment unit 60 and the disassembling operation for therecycling can easily be performed from the outside of the outer tub 2.If the electrodes 33 were disposed between the outer tub 2 and the innertub 5, there would be a need for an additional space in the outer tub 2and additional water to be retained in the space. Where the watertreatment unit 60 is mounted on the outer surface of the outer tub 2, onthe other hand, the need for the additional space and the additionalwater is obviated.

[0075] It is herein merely necessary that the water treatment unit 60which ensures easy implementation of the aforesaid operations isprovided as a unit separate from the outer tub 2 and unitarily handled.For example, the water treatment unit 60 may include the pair ofelectrodes 33 and the fixing portions 80 for fixing the unit to theouter tub 2, and be adapted to electrolyze the water in use for thewashing process by its own or in cooperation with the outer tub 2 toimpart the water with a cleaning capability without addition of thedetergent.

[0076] The water treatment unit 60 is detachable from the outer tub 2,so that the detaching operation can highly conveniently be performed.Where the electrodes 33 contain a precious metal, easy recycling isadvantageously ensured.

[0077] Since the water treatment unit 60 incorporates the electrolyzingchamber 32 and the pair of electrodes 33, the water treatment unit 60can unitarily be handled for the mounting and maintenance operations.Thus, these operations can further be facilitated.

[0078] Since the electrodes 33 are supported at the opposite sidesthereof within the box-shaped electrolyzing chamber 32, the watertreatment unit 60 can be handled without careful attention. Therefore,the assembling, maintenance and disassembling operations can further befacilitated. In addition, there is no possibility that the electrodes 33are displaced or dislodged in the electrolyzing chamber 32 due to thevibrations of the outer tub 2 during the dehydrating operation.

[0079] With the packings 81 provided between the water treatment unit 60and the outer tub 2, dimensional errors in the outer tub 2 and thecorresponding portion of the water treatment unit 60 can be accommodatedby elastic deformation of the packings 81 when the water treatment unit60 is mounted on the outer tub 2, so that the mounting can easily beachieved. In addition, the sealing of the gap between the watertreatment unit 60 and the outer tub 2 can be achieved. Therefore,bonding for the sealing can be obviated, so that labor for theassembling operation can be alleviated and the detaching anddisassembling operations can be facilitated.

[0080] By the provision of the pair of water communication paths 34, 35,the water inlet path and the water outlet path between the electrolyzingchamber 32 and the outer tub 2 can be separated, whereby the water iscaused to efficiently flow between the electrolyzing chamber 32 and theouter tub 2. Thus, the treated water can be supplied into the outer tub2 for effective use in the washing process without wastage, so that thecleaning capability and the sterilizing capability can be enhanced.Further, the water from the outer tub 2 is caused to flow within theelectrolyzing chamber 32 for efficient electrolysis.

[0081] The pair of water communication paths 34, 35 are spaced apartfrom each other, so that the treated water is prevented from flowingback into the electrolyzing chamber 32 immediately after flowing out ofthe electrolyzing chamber 32.

[0082] The pair of water communication paths 34, 35 are provided atdifferent vertical positions of the thin-box-shaped electrolyzingchamber. 32 provided on the outer surface 66 of the outer tub 2, so thatthe stagnation of the water and the trapping of air can be suppressed.Thus, the water is caused to flow vertically (in a direction indicatedby an arrow in FIG. 3) for efficient electrolysis.

[0083] Where the water flows upward in the electrolyzing chamber 32, theprovision of the upper water communication path 34 at the inclined upperportion 69 of the electrolyzing chamber 32 permits the water flowingupward in the electrolyzing chamber 32 to be guided along theinclination into the upper water communication path 34 to speedily flowout, thereby facilitating the water flow. The lower water communicationpath 35 provided at the lower end of the electrolyzing chamber 32prevents the stagnation of the water in the electrolyzing chamber 32.This advantageously facilitates the water flow in the electrolyzingchamber 32.

[0084] It is preferred that the electrodes 33 are thus provided in aspace where the water flows to ensure efficient electrolysis. It isparticularly preferred that the electrodes 33 are provided in a spacewhere the water is circulated with respect to the outer tub 2. Thus, theuse efficiency of the electrolyzed water can be enhanced. For example,it is conceivable that a circulation mechanism is provided for forciblycirculating the water by sucking the water from the outer tub 2 throughan inlet thereof and discharging the water through an outlet thereof,and the electrodes 33 are provided in the circulation mechanism. Thecirculation mechanism may comprise a tubular water passage for watercommunication between an upper portion and a lower portion of the outertub 2, and an electric pump for causing the water to pass through thewater passage. The construction of such a circulation mechanism isdisclosed in Japanese Patent Application No. 2000-196894 and the likefiled by the applicant of the present invention. Besides, a knownconstruction for the water circulation may be employed.

[0085] Since the electrolyzing chamber 32 has a thin box shape having asmaller depth with respect to the outer surface of the outer tub 2, theprojection of the water treatment unit 60 from the outer surface of theouter tub 2 can be reduced. Where the electrolyzing chamber 32 is of athin type fitted on the outer side surface 66 as the outer surface ofthe outer tub 2, for example, an increase in the size of the housing 1is suppressed which may be required for prevention of the bump of thewater treatment unit 60 against the housing 1 during the dehydratingoperation as described above. Thus, space saving can be achieved. Wherethe electrolyzing chamber 32 is of a thin type fitted on the bottom 64as the outer surface of the outer tub 2, the piping arrangement for thedrainage of used water from the electrolyzing chamber 32 can besimplified, thereby achieving space saving.

[0086] Where the electrolyzing chamber 32 is provided below the outertub 2, e.g., below the bottom 64 and the outer side surface 66, waterretained at a lower water level within the outer tub 2 can also beutilized. For example, the electrolyzing process can be started in themidst of the water supply to the outer tub 2, so that the time requiredfor the electrolysis can be reduced. Further, a course in which theelectrolyzed water is utilized at a lower water level can be realized.

[0087] Where the electrolyzing chamber 32 is provided on the outer sidesurface 66 of the outer tub 2 and the water communication path 35 isprovided at the lower end of the electrolyzing chamber 32, the water inthe electrolyzing chamber 32 is allowed to flow out into the outer tub 2through the water communication path 35 during the water drainage fromthe outer tub 2.

[0088] It is also conceivable that at least a part of the electrolyzingchamber 32 is formed integrally with the outer tub 2. In this case, theelectrolyzing chamber 32 is preferably provided so as to project outwardfrom the outer surface of the outer tub 2 or to be recessed along theinner surface of the outer tub 2. Thus, the interior configuration ofthe outer tub 2 can generally properly be maintained, thereby preventingreduction in space efficiency within the outer tub 2 and increase inwater consumption more than necessary. Where the inner surface of theelectrolyzing chamber 32 and the inner surface of the outer tub 2 arecontinuous, these inner surfaces are preferably inclined with respect toeach other to facilitate the water flow between the inside of the outertub 2 and the inside of the electrolyzing chamber 32.

[0089] In the meantime, the water from the outer tub 2 is oftencontaminated with lint. If the lint adheres on the electrodes 33, thereis a fear that the durability of the electrodes 33 and the electrolysisefficiency are reduced. Therefore, a problem associated with the lintentering into the water treatment unit 60 is solved in the followingmanner.

[0090] Corner portions 82 of the electrodes 33 each have an R-shape 83(partly shown in FIG. 4). Thus, the electrodes 33 have no corner edge,so that the lint is less liable to be caught on the corner portions ofthe electrodes 33 and easily released. Even if the lint is caught on thecorner portions 82, the lint is naturally released from the cornerportion 82 by the water streams.

[0091] The R-shape 83 includes an R-shape as seen perpendicularly to theplate surface of the electrode 33, and an R-shape as seen along theplate surface of the electrode 33. At least some of the corner portionsmaybe rounded, but it is preferred that more of the corner portions,particularly, all the corner portions, are rounded.

[0092] The spacing (D3) between the electrodes 33 is determined so as toprevent the lint from being caught therebetween. The spacing ispreferably not smaller than 2 mm, for example. If the spacing is smallerthan 2 mm, the lint is liable to be caught. Further, a spacing (D4)between the electrode 33 and the electrolyzing chamber 32 may be thesame as the aforesaid spacing, or zero. That is, there may be no gapbetween the electrodes and the electrolyzing chamber 32.

[0093] This prevents reduction in water fluidity due to adhesion of thelint. This also prevents the lint from hindering the contact of thewater with the electrodes 33. As a result, the reduction in electrolysisefficiency due to the lint can be prevented, so that the electrolysisefficiency can be maintained at a higher level. Since the lint ispermitted to enter the water treatment unit 60, there is no need forprovision of a lint filter and maintenance against the lint.

[0094] As shown in FIG. 2, the washing machine may have an air bubblegenerator 88 for generating air bubbles from the bottom 64 of the outertub 2 for enhancement of the cleaning capability. Where the air bubblegenerator 88 and the water treatment unit 60 are used in combination,the electrolysis can be achieved more efficiently.

[0095] The air bubble generator 88 includes an air pump 89, an air hose90 connected to an air outlet of the air pump 89 for air supply, and anozzle (not shown) connected to an end of the air hose 90 for ejectingair into the outer tub 2. When the air bubble generator 88 is actuatedin the washing process, the air is ejected from the nozzle, and flowsinto the inner tub 5 through the perforations of the inner tub 5 togenerate air bubbles below the pulsator 7. The air bubbles are agitatedby the rotating pulsator 7, and broken into a multiplicity of minute airbubbles. When the minute air bubbles are brought into contact with thelaundry, the minute air bubbles are broken to generate ultrasonic waves.At this time, shock waves within an ultrasonic range are generated,thereby promoting removal of dirt components adhering onto the laundry.Thus, the cleaning capability can be enhanced as compared with a casewhere air bubbles are not applied.

[0096] The air bubble generator 88 has a function as air supplying meansfor supplying air into the electrolyzing chamber 32 from a lower portion70 of the electrolyzing chamber 32 in addition to the originallyintended function for enhancing the cleaning capability. The airsupplying means generates water streams by promoting upward water flowwithin the electrolyzing chamber 32 of the water treatment unit 60. Theair hose 90 is branched in a middle portion thereof. One branch extendsto the nozzle, and the other branch is connected to the electrolyzingchamber 32.

[0097] A single air supply port 91 is provided in the lower portion 70of the electrolyzing chamber 32 so as to be supplied with the air fromthe air hose 90 as shown in FIG. 4. A plurality of air supply ports 91maybe provided. The air pump 89 is actuated in the electrolyzingprocess. The air supplied into the electrolyzing chamber 32 from the airsupply port 91 is broken into air bubbles E, which float in theelectrolyzing chamber 32 to flow into the outer tub 2 through the upperwater communication path 34 (in a direction indicated by aone-dot-and-dash line in FIG. 4). Correspondingly, the water retained inthe electrolyzing chamber 32 is caused to flow by the flow of the air(in a direction indicated by a broken line in FIG. 4). Particularly,where the upper portion 69 of the electrolyzing chamber 32 is inclinedand the water communication path 34 is located at the higher position,the air bubbles can quickly flow out of the electrolyzing chamber 32, sothat the water flow can further be facilitated. There is no possibilitythat the air bubbles are trapped between the electrodes 33. As a result,the electrolysis efficiency can be enhanced. Therefore, a voltagerequired to provide a predetermined electrolyzing capability can bereduced, thereby realizing reduction in size, cost and power consumptionof the electrical components such as the transformer 61.

[0098] The air supply port 91 is disposed so as not to overlap with theelectrodes 33 as seen in plan and so as not to face toward theelectrodes 33. Thus, the air can be supplied without contact with theelectrodes 33. Therefore, reduction in electrolysis efficiency due tothe air can be suppressed. It is preferred that the air supply port 91is horizontally spaced a predetermined distance from edges of theelectrodes 33 in a corner of the bottom face portion 76 of theelectrolyzing chamber 32. The predetermined distance is a distance suchas not to permit the contact of the air with the electrodes 33, forexample, 10 mm.

[0099] The air supply port 91 and the upper water communication path 34are disposed at diagonally opposite positions as seen from the frontside. Thus, the air can flow a longer distance in the electrolyzingchamber 32, so that the water flow can be facilitated. The air supplyport 91 and the lower water communication path 35 are disposed atlaterally separate positions as seen from the front side. Thus, waterpresent in a position remote from the lower water communication path 35is caused to easily flow, which may otherwise have a difficulty inflowing.

[0100] Thus, the water flow in the electrolyzing chamber 32 can befacilitated for efficient electrolysis. In addition, the air isintroduced into the outer tub 2 for improvement of the cleaningcapability. The aforesaid air pump 89 may be adapted to supply the aironly to the electrolyzing chamber 32. Referring back to FIG. 1, thefollowing explanation is directed to a case where the air bubblegenerator 88 is not provided.

[0101] A top plate 18 is provided on a top face of the housing 1. Thetop plate 18 has a laundry loading port 18 a provided in a centerportion thereof. The loading port 18 a is covered with an openable upperlid 19. An operation panel 48 is provided in front of the top plate 18.

[0102]FIG. 5 is a plan view of the operation panel 48. The operationpanel 48 includes an operation section 21 and a display section 28. Theoperation section 21 has a power supply key 49 for turning on powersupply to the machine, a start key 36 for starting a washing process,and a set of course keys 37 (selecting means) for selecting a washingcourse. The course key set 37 includes a standard course key 38 forselecting a standard course, a self-arranged course key 39 for selectinga self-arranged course, a fast course key 40 for selecting a fastcourse, a thorough rinsing course key 41 for selecting a thoroughrinsing course, and a zero detergent course key 42 for selecting a zerodetergent course.

[0103] The standard course is a washing course in which a standardwashing process is performed. The self-arranged course is a washingcourse in which a washing process is performed according to a procedureset by a user (manually set procedure). The fast course is a washingcourse in which a washing process time is short. The thorough rinsingcourse is a washing course in which a rinsing operation is thoroughlyperformed by increasing a rinsing operation period and the number oftimes of the rinsing operation. These courses employ a detergent. Inthese courses, water containing the detergent (detergent solution) isretained in the outer tub 2 and the laundry is washed by generatingwater streams by the rotation of the pulsator 7. These courses arecollectively referred to as a first washing course.

[0104] The zero detergent course employs no detergent. In this course,water retained in the outer tub 2 is electrolyzed by the electrolyzingdevice 31 for production of electrolyzed water, and the laundry iswashed by generating water streams by the rotation of the pulsator 7.The zero detergent course is referred to as a second washing course.

[0105] The display section 28 includes a course display section 43 fordisplaying a selected washing course, a detergent amount display section44 (information means) for displaying the amount of the detergentcorresponding to the load of the laundry, and a zero detergent displaysection 45 (second information means) for indicating addition of nodetergent by lighting an LED. In the course display section 43, LEDs 46are provided in the vicinity of the respective course keys, and one ofthe LEDs corresponding to the selected washing course is lighted. In thedetergent amount display section 44, a plurality of LEDs 47 are providedin an illustration of a detergent measure cup, and a number of LEDs 47corresponding to the amount of the detergent are lighted for indicationof the detergent amount.

[0106]FIG. 6 is a diagram illustrating the electrical construction ofthe fully automatic washing machine according to this embodiment. Acontrol center is a control section 20 including a CPU, a RAM, a ROM, atimer and the like. The control section 20 is comprised of amicroprocessor. An operation signal is inputted to the control section20 from the operation section 21. A water level detection signal isinputted to the control section from a water level sensor 22 fordetecting the level of the water contained in the outer tub 2. Thecontrol section 20 controls the rotation of the motor 8 via the invertordriving section 23, and controls the operation of the torque motor 26and the operation of the water supply valve 13 via a load drivingsection 25. The torque motor 26 controls the operation of the clutch 27and the operation of the water drainage valve 15 as described above.Further, the control section 20 controls the operation of the displaysection 28 and the operation of a buzzer 29 for notifying the end of theprocess and an abnormality in the process. The motor 8 is provided witha rotation sensor 24 for outputting pulse signals according to therotation thereof, and the pulse signals are inputted to the controlsection 20. The rotation sensor 24 is provided for detecting therotation speed of the motor 8, i.e., the rotation speed of the inner tub5.

[0107] The pair of electrodes 33 are connected to an output side of thecontrol section 20 via the energization circuit 30 including thetransformer 61 and the like. When an energization signal is outputtedfrom the control section 20, the energization circuit 30 is actuated forenergization of the pair of electrodes 33.

[0108] Sequences for the respective washing courses are stored in theROM 20 a of the control section 20.

[0109] When a washing course is selected by the operation of the coursekey set 37, a sequence for the selected washing course is read out ofthe ROM 20 a. Then, the control section 20 controls loads to be appliedto the motor 8 and the like according to the sequence, and performs thewashing process according to the selected washing course.

[0110] An explanation will be given to the operation of the fullyautomatic washing machine having the aforesaid construction according tothis embodiment. With reference to a flow chart in FIG. 7, there willfirst be described a case where a user selects the standard course whichis a typical washing course employing a detergent.

[0111] When the start key 36 is pressed to provide a command for thestart of the washing process, the load or the amount of laundry loadedin the inner tub 5 is detected prior to the supply of water (Step S1).More specifically, the pulsator 7 is rotated for a short period of time,and the load is determined on the basis of a period during which theconsequent inertial rotation continues. In this case, load detectionmeans is constituted by the pulsator 7 and the control section 20. Ofcourse, the detection of the load is not limited to this method, but anyother method may be employed.

[0112] Next, a washing water level is determined according to thedetected load (Step S2), and a detergent amount corresponding to theload is displayed on the detergent amount display section 44 (Step S3).In view of the display in the detergent amount display section 44, auser adds a proper amount of a detergent into the inner tub 5.

[0113] In turn, the supply of tap water is started, and the water issupplied to the determined washing water level (Steps S4 to S6). Thus, adetergent solution obtained by dissolving the detergent in the tap wateris contained in the outer tub 2.

[0114] Subsequently, the pulsator 7 is rotated at a predetermined speedin one direction or in opposite directions, whereby water streams aregenerated in the outer tub 2 for washing the laundry (Step S7). Dirtadhering to the laundry is removed by the effects of the detergent andthe water streams. After a lapse of a predetermined washing period, thepulsator 7 is stopped to end the washing operation (Steps S8, S9).

[0115] After the washing operation is completed, a first intermediatedehydrating operation, a first rinsing operation, a second intermediatedehydrating operation, a second rinsing operation and a finaldehydrating operation are sequentially performed. Thus, the washingprocess is completed.

[0116] With reference to a flow chart in FIG. 8, an explanation will begiven to a case where the user selects the zero detergent course whichemploys no detergent.

[0117] When the start key 36 is pressed to provide a command for thestart of the washing process, the LED of the zero detergent displaysection 45 is lighted instead of the display in the detergent amountdisplay section 44 (Step S11). Thus, the user is notified that nodetergent is added.

[0118] Then, the supply of tap water is started (Step S12) The water issupplied to a predetermined washing water level (more specifically alower water level) for the zero detergent course. When the water levelin the outer tub 2 reaches a predetermined level which is lower than thewashing water level and permits the pair of electrodes 33 of theelectrolyzing device 31 to be submerged in the water, the electrolyzingdevice 31 is actuated, i.e., the pair of electrodes are energized (StepsS13, S14). Further, the pulsator 7 is rotated at a predetermined speedin one direction or in opposite directions to generate water streams inthe outer tub 2 (Step S15).

[0119] The tap water contains very small amounts of impurities such asiron, calcium, magnesium and chlorine. Therefore, electrolyzed water isproduced through the electrolyzing process performed in theelectrolyzing chamber 32, and the tap water goes back and forth betweenthe electrolyzing chamber 32 and the outer tub 2, whereby the outer tub2 is gradually filled with the electrolyzed water. The electrolyzedwater has a weak alkalinity. Further, active oxygen as well ashypochlorous acid (HClO) and hypochlorous ions (ClO—) are generated inthe electrolyzed water in the electrolyzing chamber 32. Together withthe electrolyzed water, hypochlorous acid and hypochlorous ions flowinto the outer tub 2. In the outer tub 2, dirt adhering to the laundryis removed by the effect of the alkaline water and the effect of thewater streams. Further, the laundry is sterilized by the effect ofhypochlorous acid and hypochlorous ions. The dirt removed from thelaundry is decomposed by the effect of the active oxygen in theelectrolyzing chamber 32, and prevented from adhering again to thelaundry.

[0120] When the water reaches the washing water level, the water supplyis stopped (Steps S16, S17). On the other hand, the operation of theelectrolyzing device 31 and the operation of the pulsator 7 arecontinued. After a lapse of a predetermined washing period, theoperation of the electrolyzing device 31 (the energization of the pairof electrodes 33) is stopped, and the pulsator 7 is stopped forcompletion of the first washing operation (Steps S18 to S20).

[0121] After an intermediate dehydrating operation is performed, asecond washing operation is performed in the same manner as the firstwashing operation. Upon completion of the second washing operation, afinal dehydrating operation is performed. Thus, the washing process inthe zero detergent course is completed.

[0122] In the washing course employing the detergent, e.g., in thestandard course, the electrolyzing device 31 may be operated in therinsing operations (first and second rinsing operations), so that theelectrolyzed water is employed for rinsing the laundry. Thus, thelaundry can be sterilized while being rinsed.

[0123] An automatic detergent adding device (adding means) may beprovided for automatically adding a proper amount of the detergentaccording to the detected load. Thus, the detergent is automaticallyadded in the washing course employing the detergent, e.g., in thestandard course, and no detergent is added in the zero detergent course.A conventionally known device may be used as the automatic detergentadding device and, therefore, no explanation will be given to theconstruction thereof.

[0124] While the embodiment of the present invention has thus beendescribed, it should be understood that the invention be not limited tothe above-described embodiment as will be described below.

[0125] The washing machine according to the present invention is notlimited to the fully automatic washing machine. The invention isapplicable to a so-called drum type washing machine in which the washingtub is constituted by an outer tub and a drum of horizontal axis typeprovided in the outer tub. Further, the invention is applicable to aso-called double tub washing machine in which a single washing tub isprovided separately from a dehydration tub.

[0126] The water treatment means according to the present invention isnot limited to the electrolyzing device, but any treatment means may beemployed which performs a specific treatment on tap water to impart thetap water with the cleaning capability. Further, the present inventionis not limited to the electrolysis of the tap water alone. For promotionof the electrolysis of the tap water, the electrolyzing process may beperformed on an electrolytic solution prepared by adding salt or sodiumhydrogencarbonate to the tap water.

[0127] The water stream generating means according to the presentinvention is not limited to the pulsator. For example, the water streamsmay be generated by rotating the inner tub. In this case, the inner tubserves as the water stream generating means. What is important is thatthe water stream generating means is capable of generating water streamswithin the washing tub.

[0128] The information means and the second information means accordingto the present invention are not limited to the display means such asthe detergent amount display section and the zero detergent displaysection. For example, means for notifying the amount of the detergentand the non-addition of the detergent by voice may be employed.

[0129] It should be understood that the present invention be not limitedto the embodiment described above, but various modifications may be madewithin the scope of the present invention as defined by the appendedclaims.

[0130] This application claims priority benefits under the Convention onthe basis of Japanese Patent Applications No. 2001-106923 and No.2001-133254 filed with the Japanese Patent Office on Apr. 5, 2001 and onApr. 27, 2001, respectively, the disclosure thereof being incorporatedherein by reference.

What is claimed is:
 1. An electric washing machine comprising: a washingtub for containing laundry; water stream generating means for generatingwater streams in the washing tub; water treatment means for performing aspecific treatment on tap water to be supplied into the washing tub ortap water supplied into the washing tub to impart the water with acleaning capability without addition of a detergent; storage means whichstores therein a sequence for a first washing course in which thelaundry is washed by generating water streams in the washing tub whichcontains a detergent solution prepared by adding the detergent into thetap water, and a sequence for a second washing course in which thelaundry is washed without the use of the detergent by generating waterstreams in the washing tub which contains a cleaning liquid impartedwith the cleaning capability by treating the tap water by the watertreatment means; selecting means for allowing a user to select the firstwashing course or the second washing course; and control means forcontrolling operations of the water stream generating means and thewater treatment means on the basis of the sequence for the washingcourse selected by the selecting means to perform a washing process inthe selected washing course.
 2. An electric washing machine as set forthin claim 1, wherein the water treatment means comprises a pair ofelectrodes for electrolysis of the tap water, and produces the cleaningliquid by electrolyzing the tap water through energization of the pairof electrodes.
 3. An electric washing machine as set forth in claim 1 or2, further comprising: load detecting means for detecting a load of thelaundry; and information means for notifying a detergent amountaccording to the load detected by the load detecting means, wherein thecontrol means actuates the load detecting means for the detection of theload and causes the information means to notify the detergent amountaccording to the detected load in the washing process of the firstwashing course, and prohibits the information means from notifying thedetergent amount in the washing process of the second washing course. 4.An electric washing machine as set forth in claim 3, further comprising:second information means for notifying that no detergent is added,wherein the control means actuates the second information means in thewashing process of the second washing course.
 5. An electric washingmachine as set forth in claim 1 or 2, further comprising: load detectingmeans for detecting a load of the laundry; and adding means for addingthe detergent in an amount according to the load detected by the loaddetecting means, wherein the control means actuates the load detectingmeans for the detection of the load and causes the adding means to addthe detergent in the amount according to the detected load in thewashing process of the first washing course, and prohibits the addingmeans from adding the detergent in the washing process of the secondwashing course.
 6. An electric washing machine which selectively effectsa first washing course in which laundry is washed with the use of adetergent and a second washing course in which the laundry is washed ina manner different from the first washing course without the use of thedetergent.
 7. An electric washing machine comprising a water treatmentunit for electrolyzing water in use for a washing process to impart thewater with a cleaning capability without addition of a detergent, thewater treatment unit being attached to the outside of a washing tub. 8.An electric washing machine as set forth in claim 7, wherein the washingtub comprises an outer tub for containing water, and an inner tubprovided in the outer tub, wherein the water treatment unit is attachedto the outside of the outer tub.
 9. An electric washing machine as setforth in claim 7 or 8, wherein the water treatment unit comprises anelectrolyzing chamber, at least one pair of electrodes disposed in theelectrolyzing chamber, and a pair of water communication paths extendingfrom the electrolyzing chamber, the pair of water communication pathsbeing connected to the washing tub, wherein the water flows into theelectrolyzing chamber from the washing tub through one of the watercommunication paths, and the water treated in the electrolyzing chamberflows out into the washing tub through the other water communicationpath.
 10. An electric washing machine as set forth in claim 9, whereinthe electrolyzing chamber has a thin box shape having a smaller depthwith respect to an outer surface of the washing tub, wherein theelectrodes each have a plate shape corresponding to the thin box shapeof the electrolyzing chamber, and the plate-shaped electrodes aredisposed at a predetermined inter-electrode pitch with opposite edgesthereof being supported.
 11. An electric washing machine as set forth inclaim 10, wherein the electrolyzing chamber is mounted on an outer sidesurface of the washing tub, wherein the one water communication path(inlet path) extends from a lower portion of the electrolyzing chamber,wherein the other water communication path (outlet path) extends from anupper portion of the electrolyzing chamber, wherein the watercommunication paths are connected to the washing tub with theintervention of packings.
 12. An electric washing machine as set forthin claim 11, wherein the upper portion of the electrolyzing chamber isinclined with one side thereof located at a higher position, and theoutlet path extends from the higher position, wherein the inlet pathextends from a lower end of the electrolyzing chamber.
 13. An electricwashing machine as set forth in claim 12, wherein an air supply port forsupplying air is provided at a lower portion of the electrolyzingchamber, whereby the air supplied into the electrolyzing chamber fromthe air supply port flows into the washing tub through the upper watercommunication path, and the water contained in the electrolyzing chamberis caused to flow by the air flow.
 14. An electric washing machine asset forth in claim 13, wherein the air is supplied without contact withthe electrodes.
 15. An electric washing machine as set forth in claim 9,wherein the electrodes each have a round corner, and a spacing betweenthe electrodes and a spacing between each of the electrodes and theelectrolyzing chamber are such that lint is prevented from being caughttherebetween.